Now that you have seen how to drive traffic without spending money, you may want to see how the traffic you drive affects your earnings.
First, all your Google Adsense Ads at every position must be from a different Ad units. This will help you track which Ad is making you the most money. You may also decide to switch from responsive to 300X250 ads. Make sure you record the date of this change.
After some days, compare the data from when the Ad was responsive and when the block Ad was replaced and see which has the better CTR and CPC. In fact, what justifies is the final earnings.
Over a specific number of days, an Ad unit with a CPC of $0.08 might have a CTR of 1% and makes you $10 while another Ad unit with a CPC of $0.1 and a CTR of 0.8% makes $15. Even with lower CTR, I might decide to go with the latter. But remember that the reason for the rotation and changing of Ad layout was to increase CTR. From the goals of the experiment, the Ad with higher CTR but lower earnings should be chosen.
CPC might change based on user interest or on page content. So, with better CTR optimization, earnings could triple.